Chucking mechanism



July16,1963 R.w.BRowN 3,097,856

CHUCKING MECHANISM Filed May l2, 1961 2 Sheets-Sheet 2 WZZMLWfgefflffww@ n NP United States Paflf Olii@ p n `3,097,856 CHUCKINGMECHANSM 1"fRog'er W, Brown, Windsor, Vt., assigner to Cone Automatic`lVlachine Company, Inc., Windsor, Vt., a corporation `of Vermont FiledMay 12, 1961, Ser. No. 109,774

7 Claims. (Cl.` 279-4) This invention .generally relates to chuckingmechanisms' and more particularly to an improved chucking mechanismadapted 4to operate a collet. lt is a'principal object of .thisinvention t-o provide an "i improved collet chucking mechanism which iscapable of `maintaining a constant collet engaging force on its sup-"ported stock 'even thou-gh the stock varies in size from the standardsize for which the collet is specifically designed and therebyeliminates the possibility of having an excessive or an inadequatecollet engagement.

Another object of this invention `is to provide an im- "proved colletchucking mechanism that smoothly and positively operates theH lathecollet between its stocklocking and releasing positions so astoeliminate sudden or erratic collet engagement and disengagement andthe `shock on the collet and chucking mechanism produced thereby.

It is a'further object of this invention to provide an improved colletchucking mechanism `which has a simple arrangement of parts that can beeconomically mannfactured andeasily assembled andwherein adjustments inthe collet engaging force on the stock can be readily made and which`will thereafter be continuously maintained. p Other 'objectswill -beinpart obvious and in part pointed outmore in detail hereinafter.

"l HThe invention accordingly consists inthefeatures of construction',vcombination of elements and arrangement of parts which willlne-exemplified in the construction hereafter set forth 4and the scopeof the application which will beindicated in the appended claims.

' In the drawings:

3 is a cross-sectional view taken substantially `along the" line 3 3'of- FIG. 2;

FIG 4 is across-sectional view taken substantially *alongthe line 4-4 ofFIG. 2;

i FIG; 5 is a cross-sectional view' taken substantially along the line 55 of IFIG. 2;

A"-FIG. 6 is a'fragmentary cross-sectional` view taken substantiallyalong Athe line 6 6 of FIG. 3;

lFIG. 7 is :a cross-sectional view of a portion" of the spindle assemblyof FIG. 2 showingthe chucking mech- Vanism in its collet releasingposition; and

FIG. 8 is a fragmentary cross-sectional view similar 4to FIG 7`showing'the chucking mechanism in an intermediate position.

Referring to the `drawings more in detail, a'wbrk spindle assembly,generally designated Iby the numeral 8, has a work spindle 10 that isshown to be rotatably mounted rbyfthetapered roller bearing assemblies20 and 22 Within f aamultiple spindle lathe carrier "16. The spindle y10has an frerilargedwhead or collet support 12 Iwith an inwardly taperedconical bore 1-4 that is adapted to receive and engage -a collet 32having a mating external conical Surface 15. A collet operating tube orsleeve `44 is Xed to the collet and is capable of rectilinear movementalong 2 the axis 4of the Yspindle 10"b'e`tween 'a lofckirigposition(FIGLDQVWhere the collet is ini engag'nlentf'with the head .'12 forretaining the stock 3 "4, andafstock releasing positiontnot shown) wherethestock 3,4 can be fed forwardly through the collet as by the lfeedlingers 40 fixed to the feed or pusher tube 38pA s In :accordance withthis inventima chuckingfmechi anism is provided for retractingthe"collet."aridr.locking the st ocli and includes -acompensatorgeiife'rally `desighated by the numeral 41whichjisfuslidably' sdpported'upon and adapted to axially engage acolla-r 168' thatv has anadjustable threaded lengagement ywith thecolletoperating tube 44. This compensator 41 is operatedv as. bya camsleeve 24 that is actuated by'a'lever 30 btweenfa'"colletlockingposition shown by boldlines in FIG. lxand a collet releasing positionVshown "in phantom inFlG. l. L, l,

The compensator has an annular housings4 which pivotally supportsgaplurality of fingers 28Aby` pins 50.

' Each linger 28, hasJ a` yfollower orroller V2.76 rotatably mountedupon thefend thereof lwhich is adapted 'toengage a camming surface29 onthe cam sleeve 24 ,for, .trans lating the sli'ding'fmotion of the camsleeve ,24r into pivotal motion of theiingers 28. Because of theengagement by the ngerheels 51' with'acollar 52 thatabutsthe spindle 10,the pivotalV movement ofthefiinglers 28 is translatedinto"slidingjrnovenien t of thehousing 54, A

"The annular housmg 54 has anfannular cap ,164..af1ixed thereto as by aplurality of, angularlygdisposed screws str-1G. `6), to defineartemisia; marchan-ber in' which an annular piston 7.6 is adapte/dptorecipnocatewThe piston hasintegral therewith la sleeve rtlthatrisslideably 'l mounted ,on theA collar` 68, and the piston and sleeve arelocated to rdiviyde the chamberinto. a pair offluidcharnber' portions-80 land 82 -wl'lich aredfl-uidly seal-ed within the housing 54 as bytheelies rngs57, 58.antd 59 to prevent 'fluid Vleakage or .huiddpassagetherebetween Hydraulic fluid is disposed within the o hambe-rportions 80and 82 toact as afluid mediumVA thnoughwhichthe 'collet operating tubecollar 6,8.`

movement of the housing istransferred to thepiston 7.6, ywhich in|1urI,l,'V trallsfers` itsV Lmovement to the collet 32 `throilghjtheabutting engagementby the end 72 or thepistomsleeve fwith the annularportion 74 of the .a i .Oiled POSFQUL showninV FIG. 7,: anpluralitypfASprings, `90

When the compensator is angslafly dis'osed within th chamba portion 8.0.move thepiston 76`rapidly` to thejleft, Kas viewedrinthe draw-`'ings,"agai.nst` stop pins 84 on the cap 641,0., quickly .re-

lease lthe collet 32 whereupon any `excess hydraulic vfluid in theAiluidchamber `portion 82 `is discharged into, the

` 'chamber Silvia the passages 98 (-FIGS-- 2 and4), a plurality of`which areprovided to ensure I,free flow of, the

iluid to thedhainber 80, and'thefrefore 'ensure a rapid resettingof'hefionpensator for. ausubsequenti collet Jocking operation. ,y Eachoff these passages 9,8m has thereinaorte-wayisping'loadedVballcheckvvalve 94that prevents lluid" ;liow'froml [the chamber ttlbut which adapted,` to jrel/ievetliell1`1'i'cl-"l'arssurein the chamber 82 priortp ,when

soz

itwo'reate's aqcforceon' the `piston 'equal to the ,force created by ih?@i218 Vff ,h `,SPllillgs 90 "the left. initially, asshowrl 8- thehousing54 j and the" pistonfinov `i'n unison 'because of theA ,forceponlocking force on the stock 34 reaches a magnitude Where the Huidpressure in the chamber is on .the venge of unseating a second ballcheck valve 92 (FIG. 7) located in a passage 96 extending lbetween thechamber portions,

further movement of the housing S4 to (the left will be accompanied byflow of hydraulic iiuid to the chamber 82 (FIGS. 2 and 6), and thehydraulic force on ythe piston and the collet locking force on the stock34 will remain substantially constant. Accordingly, through adjustmentiof the regulating pressure of the ball check valve 92 .by the valvespring screw 93 (FIG. 2), an optimum locking force on the collet can beestablished.

The chucking mechanism of this invention, therefore, provides a simpleand accurate means by which a constant optimum collet locking engagementis maintained on the collet supported stock notwithstanding possiblesize variations in the stock. Additionally, the chucking mechanismoperates positively and smoothly and is easily adjusted for selectingthe collet locking force which is thereafter continuously maintained.

As will be apparent to persons skilled in the art, various modificationsand adaptations of the structure above described will become readilyapparent without departure firom the spirit and scope of the invention,the scope of which is defined in [the appended claims.

I claim:

1. A chucking mechanism for use with a spindle assembly having a colletsupport and a collet adapted for relative rectilinear movement thereinin stock-locking and releasing directions, comprising, a cylinder and apiston therein reciprocably mounted for movement along the axis ofrelative movement of the collet, means operably connecting the pistonand the collet assembly and moving the collet relative to the spindle inthe stocklocking direction upon movement of the piston in one direction,an hydraulic Ifluid disposed in the cylinder and adapted `when underpressure to create a force on the piston in said one direction, meansfor moving the cylinder in said one direction for pressurizing thefluid, and a pressure relief valve connected to the cylinder limitingthe maximum pressure of the hydraulic fluid.

2. A chucking mechanism in combination with a collet assembly having acollet support and a collet mountedk for relative rectilinear movementtherein in stock-locking and releasing directions, comprising, anannular cylinder and an annular piston therein mounted .for movementalong the axis :of movement of the collet, said cylinder defining withthe piston a pair of annular chambers on opposite axial sides thereof,means operably connecting the piston and the collet and moving thecollet in the one direction relative to its support upon movement of thepiston in one direction, an hydraulic fluid in said chambers, passagemeans fluidly connecting the chambers and having a one-way pressurerelief valve therein for limiting the maximum pressure of fthe hydraulicfluid in one of the chambers, and means for moving the cylinder in saidone direction.

3. The chucking mechanism defined in claim 2, further comprising, asecond -one-way pressure relief valve in said passage means limiting themaximum pressure of the hydraulic fluid in the other of said chambers.

4. A chucking mechanism in combination with a collet assembly having `acollet support and a collet mounted for relative rectilinear movementtherein in stock-locking of said chambers and limiting the maximumhydraulic pressure therein, and means for actuating the cylinder in saidone direction.

5. A chucking mechanism in combination with a collet mounted forrectilinear movement in stock-locking and releasing directions andhaving a collet operating tube fixed thereto, comprising, an annularcylinder having an annular piston slideable therein, said cylinder andpiston being mounted for movement along the axis of movement of thecollet, said cylinder defining with the piston a -pair of annularchambers on opposite sides thereof, means xed to the collet operatingtube being adapted t0 be actuated by the piston for moving the collet inthe stock-locking direction upon movement of the piston in onedirection, an hydraulic fluid disposed in said chambers, passage meansfluidly connecting the chambers for allowing hydraulic fluid flowtherebetween, means limiting the maximum pressure of the fluid in atleast one of the chambers, and means ifor moving the cylinder in saidone direction.

6. A chucking mechanism for use with a collet mounted for rectilinearmovement in stock-locking and releasing directions, comprising; acylinder having a piston slideable therein, said cylinder and pistonbeing mounted `for movement along the axis of movement of the collet,said cylinder defining with the piston a pair of chambers on oppositeaxial sides thereof, means operably connecting the piston and the colletand moving the collet in the stock-locking direction upon movement ofthe piston in one direction, spring means in a first of said chambersengaging the piston and cylinder and biasing the piston in said onedirection, an hydraulic fluid in said chambers, passage means fluidlyconnecting the chambers for providing hydraulic fluid flow therebetween,fluid pressure relief means in said passage means limiting the maximumpressure in each of the chambers, the force on the piston created by thespring means being greater than the force created on the piston by themaximum pressure in the second of said chambers, and means for movingthe cylinder in said one direction.

7. A chucking mechanism lfdr use in a lathe having in coaxialrelationship a rotating spindle, a collet with a collet operating tubefixed to the collet and adapted to move the collet in stock engaging andreleasing directions, and a sleeve selectively moved along the colletaxis for operating the chucking mechanism, comprising; an annular sleevemounted coaxially with the collet operating tube for movement along theaxis thereof, means fixed to the collet operating tube and engaged withsaid sleeve for moving -the tube in the stock-locking direction uponmovement of said sleeve in one direction, an annular piston fixed to thesleeve, an annular cylinder slideably mounted upon the sleeve anddefining with the piston a pair of annular chambers on the oppositesides thereof, spring means in a first of said chambers engaging thecylinder and the piston and forcing the piston in said one direction,stop means limiting movement of the piston within the cylinderin saidone direction, an hydraulic fluid disposed in said chambers, passagemeans fluidly connecting the chambers for allowing hydraulic fluid flowtherebetween, pressure relief means in said passages limiting themaximum pressure of the hydraulic fluid in the chambers and means movingthe cylinder in said one direction actuated by the sleeve.

References Cited in the file of this patent UNITED STATES PATENTS

1. A CHUCKING MECHANISM FOR USE WITH A SPINDLE ASSEMBLY HAVING A COLLETSUPPORT AND A COLLET ADAPTED FOR RELATIVE RECTILINEAR MOVEMENT THEREININ STOCK-LOCKING AND RELEASING DIRECTIONS, COMPRISING, A CYLINDER AND APISTON THEREIN RECIPROCABLY MOUNTED FOR MOVEMENT ALONG THE AXIS OFRELATIVE MOVEMENT OF THE COLLET, MEANS OPERABLY CONNECTING THE PISTONAND THE COLLET ASSEMBLY AND MOVING THE COLLET RELATIVE TO THE SPINDLE INTHE STOCKLOCKING DIRECTION UPON MOVEMENT OF THE PISTON IN ONE DIRECTION,AN HYDRAULIC FLUID DISPOSED IN THE CYLINDER AND ADAPTED WHEN UNDERPRESSURE TO CREATE A FORCE ON THE ISTON IN SAID ONE DIRECTION, MEANS FORMOVING THE CYLINDER IN SAID ONE DIRECTION FOR PRESSURIZING THE FLUID,AND A PRESSURE RELIEF VALVE CONNECTED TO THE CYLINDER LIMITING THEMAXIMUM PRESSURE OF THE HYDRAULIC FLUID.